1. Field
The following description relates to a Hall sensor configured to output a Hall voltage due to Hall effect and a current sensor apparatus using the same.
This research (10063287) was supported by Ministry of Trade, Industry and Energy (MOTIE) and Korea Evaluation Institute of Industrial Technology (KEIT).
2. Description of Related Art
A Hall sensor is a magnetic-electro-transducer using Hall effect. A Hall voltage VH that is an output voltage of the Hall sensor is represented by the following equation.
      V    H    =                    R        H            d        ·          I      c        ·    B  
Here, RH is a Hall coefficient, d is a thickness of a semiconductor material used as a Hall device of the Hall sensor, Ic is a Hall sensor input current that is a Hall sensor driving current, and B is a magnetic flux density.
As can be seen from the equation, the Hall voltage VH that is the output voltage of the Hall sensor is proportional to the Hall coefficient RH, the Hall sensor driving current Ic, and the magnetic flux density B, and is inversely proportional to the thickness d of the semiconductor material used as the Hall device of the Hall sensor.
Meanwhile, since the Hall sensor driving current Ic is proportional to a Hall sensor driving voltage and is inversely proportional to resistance of an input terminal of the Hall sensor, and the resistance varies according to a temperature, the Hall voltage VH that is the output voltage of the Hall sensor varies according to a temperature.
This is because the resistance occurs when a defect is present in a crystalline structure, that is, impurities hindering mobility of electrons are contained in crystals, the mobility of electrons in the crystals becomes more active as a temperature becomes higher, and the number of defects is increased such that the resistance is increased.
Accordingly, there is a need to appropriately compensate for and normalize a Hall sensor output voltage according to a temperature so as to resolve a problem in that a Hall voltage that is an output voltage of a Hall sensor varies according to a temperature. As a technique to appropriately compensate for and normalize a Hall sensor output voltage according to a temperature, a temperature compensation apparatus for a Hall sensor is proposed in Korean Patent Application Publication No. 10-2011-0114976 (Oct. 20, 2011).
This technique compensates for a temperature-dependent Hall sensor output voltage by adding a compensation voltage according to a temperature to an output voltage of a static voltage source which supplies a driving current to a Hall sensor so as to compensate for the temperature-dependent Hall sensor output voltage. A temperature of the Hall sensor should be first measured to compensate for the temperature-dependent Hall sensor output voltage.
However, in the related art, since a temperature sensor for measuring the temperature of the Hall sensor is mounted inside an application specific integrated circuit (ASIC) that is a controller for driving the Hall sensor and the Hall sensor should be installed close to the ASIC, there is a problem of a rise in temperature of the ASIC.